Microbially produced bile acids are associated with increased IgG autoantibodies and poorer mental wellbeing in fibromyalgia.

Fibromyalgia subjects had significantly higher levels of non-conjugated secondary bile acids compared to healthy controls.

• The study included 35 FM subjects and 32 matched healthy controls (HC).
• Bile acids and SCFAs were quantified using liquid chromatography coupled with high-resolution mass spectrometry.
• Non-conjugated secondary BAs, which are microbially produced, were the specific subclass elevated in FM subjects.
• Secondary bile acids are produced or altered by gut microbiota, implicating microbial involvement in FM pathophysiology.

Total bile acid levels were significantly elevated in FM subjects with high anti-SGC IgG levels compared to those with low anti-SGC IgG levels.

• Anti-SGC IgG refers to immunoglobulin G binding to satellite glial cells, previously proposed as an autoimmune marker in FM.
• Anti-SGC IgG levels were assessed with immunocytochemistry.
• This finding suggests a link between microbially produced bile acids and autoimmune activity in FM.
• FM subjects were stratified into high and low anti-SGC IgG groups for this comparison.

Concentrations of specific bile acids were associated with increased FM disease severity and poorer mental well-being.

• Associations were found between specific BA concentrations and both disease severity measures and mental well-being outcomes.
• Common FM symptoms include anxiety and depression in addition to chronic widespread pain.
• The study examined correlations between FM symptoms, anti-SGC IgG levels, and serum concentrations of 24 BAs and 11 SCFAs.
• The associations highlight a potential role for bile acids in the psychological symptoms of FM.

The study investigated alterations in both bile acid and short-chain fatty acid concentrations in FM subjects compared to healthy controls.

• 24 bile acids and 11 short-chain fatty acids were measured in serum.
• Quantification was performed using liquid chromatography coupled with high-resolution mass spectrometry.
• SCFAs, like BAs, have important immune and inflammatory functions and can be produced by gut microbiota.
• The study population consisted of 35 FM subjects and 32 matched HC.

Emerging research suggests that altered gut microbiota composition is connected to psychological symptoms in fibromyalgia.

• Gut microbiota can produce or alter bile acids and short-chain fatty acids, which have important immune and inflammatory functions.
• The authors previously proposed that autoimmunity contributes to FM based on findings of increased anti-SGC IgG in FM subjects compared to HC.
• The gut microbiota link provides a potential mechanistic pathway connecting microbial metabolites, autoimmunity, and FM symptoms.
• This background motivated the investigation of BA and SCFA concentrations as potential mediators of FM pathophysiology.